gnu.trove

Class TPrimitiveHash

java.lang.Object

gnu.trove.THash

gnu.trove.TPrimitiveHash

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

TDoubleHash, TFloatHash, TIntHash, TLongHash

public abstract class TPrimitiveHash
extends THash

The base class for hashtables of primitive values. Since there is no notion of object equality for primitives, it isn't possible to use a `REMOVED' object to track deletions in an open-addressed table. So, we have to resort to using a parallel `bookkeeping' array of bytes, in which flags can be set to indicate that a particular slot in the hash table is FREE, FULL, or REMOVED. Created: Fri Jan 11 18:55:16 2002

Version:

$Id: TPrimitiveHash.java,v 1.3 2002/09/20 20:55:58 ericdf Exp $

Author:

Eric D. Friedman

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	_states flags indicating whether each position in the hash is FREE, FULL, or REMOVED
protected static byte	FREE flag indicating that a slot in the hashtable is available
protected static byte	FULL flag indicating that a slot in the hashtable is occupied
protected static byte	REMOVED flag indicating that the value of a slot in the hashtable was deleted

Fields inherited from class gnu.trove.THash

_free, _loadFactor, _maxSize, _size, DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR

Constructor Summary

Constructors

Constructor and Description
TPrimitiveHash() Creates a new THash instance with the default capacity and load factor.
TPrimitiveHash(int initialCapacity) Creates a new TPrimitiveHash instance with a prime capacity at or near the specified capacity and with the default load factor.
TPrimitiveHash(int initialCapacity, float loadFactor) Creates a new TPrimitiveHash instance with a prime capacity at or near the minimum needed to hold initialCapacity elements with load factor loadFactor without triggering a rehash.

Method Summary

Methods

Modifier and Type	Method and Description
protected int	capacity() Returns the capacity of the hash table.
java.lang.Object	clone()
protected void	removeAt(int index) Delete the record at index.
protected int	setUp(int initialCapacity) initializes the hashtable to a prime capacity which is at least initialCapacity + 1.

Methods inherited from class gnu.trove.THash

clear, compact, ensureCapacity, isEmpty, postInsertHook, rehash, size, trimToSize

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_states

protected transient byte[] _states

flags indicating whether each position in the hash is FREE, FULL, or REMOVED

FREE

protected static final byte FREE

flag indicating that a slot in the hashtable is available

See Also:

Constant Field Values

FULL

protected static final byte FULL

flag indicating that a slot in the hashtable is occupied

See Also:

Constant Field Values

REMOVED

protected static final byte REMOVED

flag indicating that the value of a slot in the hashtable was deleted

See Also:

Constant Field Values

Constructor Detail

TPrimitiveHash

public TPrimitiveHash()

Creates a new THash instance with the default capacity and load factor.

TPrimitiveHash

public TPrimitiveHash(int initialCapacity)

Creates a new TPrimitiveHash instance with a prime capacity at or near the specified capacity and with the default load factor.

Parameters:

initialCapacity - an int value

TPrimitiveHash

public TPrimitiveHash(int initialCapacity,
              float loadFactor)

Creates a new TPrimitiveHash instance with a prime capacity at or near the minimum needed to hold initialCapacity elements with load factor loadFactor without triggering a rehash.

Parameters:

initialCapacity - an int value

loadFactor - a float value

Method Detail

clone

public java.lang.Object clone()

Overrides:

clone in class THash

capacity

protected int capacity()

Returns the capacity of the hash table. This is the true physical capacity, without adjusting for the load factor.

Specified by:

capacity in class THash

Returns:

the physical capacity of the hash table.

removeAt

protected void removeAt(int index)

Delete the record at index.

Overrides:

removeAt in class THash

Parameters:

index - an int value

setUp

protected int setUp(int initialCapacity)

initializes the hashtable to a prime capacity which is at least initialCapacity + 1.

Overrides:

setUp in class THash

Parameters:

initialCapacity - an int value

Returns:

the actual capacity chosen